Re: Faking the same LAN over the Internet

Use OpenVPN in bridged mode or if it's too complicated for you to set it up you can give a shot for Hamachi which was made for exactly this.

There is one caveat regarding using the bridged mode in openvpn that there is more packet overhead than if you would be using the routed tun network but I guess it will be more than enough for your application.

Other thing can be broadcast storm some misbehavior of bridge interfaces (like sometimes your FW thinks the packet come in on br0 sometimes on tap0), mtu problems that is also why ovpn team wants to remove the bridged mode so enjoy it while you can :)



‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Tuesday, March 31, 2020 11:34 AM, Chris Rawnsley <chris@puny.agency> wrote:

> In the period of The Great Isolation, a friend and I wish to play
> a game that has LAN-only multiplayer. We, however, live in different
> locations and, more importantly, different LANs. An often cited
> approach to solving this is to set up a VPN and connect the two
> devices to it. This requires that both devices run a VPN client
> that connects to the third device that manages the connection. And
> then, hey presto! You have a "LAN".
>
> The complication I have found is that we are both using a Nintendo
> Switch (NinSw) and this device comes without a VPN client. Initially,
> I thought it would be possible to use a VPN client on a computer
> which was wired in over Ethernet and then share the wireless to the
> NinSw. This setup would be mirrored on the other side. The diagram
> below tries to make this clearer. Search for "Where my thinking"
> to skip over this.
>
> |````````````|
> | | .________.
> | | ) ) ) |:| |:|
> |............| `========' .---/::::::::::::::\\ [NinSw] | [laptop] | [VPN] | | \\ / | _\\______/_`-----| ... |----[uplink]----// mirrored on the other side
> ``````````
> [gateway]
>
> Where my thinking comes stuck is how the wired connection is shared
> to the NinSw over wireless. The laptop, running MacOS in the case
> of my friend, will setup its own NAT to isolate the wireless
> connections from the uplink. The NinSw is then unable to receive
> an IP from the VPN and therefore not appear as part of the same
> network.
>
> Ignoring the particular case of how "Internet Connection Sharing"
> works on MacOS, would it be possible to setup some "VPN bridge"
> (yes, I made that up) on OpenBSD where it handles the details of
> the VPN connection but forwards the IP address to another device?
>
> If anyone has more insight into this and can point me in the right
> direction I would be grateful. Similarly if there's been a mistake
> in my thinking please point it out as that could help too.
>
>
> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Chris Rawnsley
>
> P.S. the game in question is Civilization 6 and, yes, they very
> annoyingly restricted it to LAN-only multiplayer...